Fiber composite materials have wide application in the automotive and aerospace industries. These materials are lightweight, while offering good strength and rigidity.
Fiber composite laminates or parts may typically be manufactured by first impregnating the fiber reinforcement with resin to form a prepreg, and then consolidating two or more layers of prepreg into a laminate. Although also useful for bonding the individual layers of prepreg together, the consolidation step may also be necessary to reduce or eliminate voids in the resulting laminate. These voids in turn, may result from the inefficient penetration of the resin in to the fiber bundle, tow, or roving.
Consolidation can be an undesirable method for forming the individual layers of prepreg into a laminate as well as removing the voids that may be present therein. This is because consolidation can require the application of heat and pressure, and thus, the use of the expensive equipment capable of applying such conditions, e.g., autoclaves, for extended periods of time. For some applications, the size of the part, and the corresponding cost of the specialized equipment required, may render consolidation cost prohibitive. Further, outgasing that may occur during consolidation may actually produce voids in the laminate and/or prepregs,
In recent years, low cost methods for removing voids from prepregs and/or preparing laminates from the same have been developed that do not require application of pressure. However, generally speaking, these methods may leave undesirable residual voids in the prepregs and/or laminates processed via such methods. As a result, parts prepared from such laminates can exhibit compromised strength.
Other methods utilized for reducing voids in laminates prepared from prepregs include reducing the viscosity of the resin prior to impregnation so that it will more readily and uniformly flow onto and into the reinforcing material. For example, such methods have provided for heating the resin or diluting the same with solvents. However, although generally useful, these methods may not completely eliminate the problem of voids in laminates prepared from prepregs.
It is desirable to provide improved apparatus and methods for uniformly infusing resin into reinforcing materials, such as fibers, fiber bundles, tows, roving or plies. Desirably, the apparatus/method provided would be capable of ready incorporation into existing methods, or combination with existing apparatus, for providing layups of prepregs